Experiments will be continued to evaluate the antiplaque activity of polymeric polyphosphonates (PPP) as well as their anticariogenic activity in vivo. Experiments will be continued to elucidate the effect of PPP on bone formation and resorption in the Redi ectopic bone model. Different polymeric polyphosphonates with well defined molecular weight ranges will be studied in view of the effect of molecular weight of the polymer on the efficacy of biological action of PPP.